To realize the full potential of communication networks, there has to exist a standardized system so that the users can engage in electronic transactions with the same degree of trust as associated with paper-based transactions.
For this reason, PKI has been developed as the primary platform for global commerce and communications. PKI insures that sensitive electronic communications are private and protected from tampering. PKI is used for digital signatures, authentication and encryption.
PKI is based on the use of cryptography, which means scrambling of information by a mathematical formula and a virtual key, so that only an authorized party using a related key can decode it. A PKI uses pairs of cryptographic keys provided by a trusted third party known as a Certification Authority (CA). Central to the workings of a PKI, a CA issues digital certificates that identify the holder's identity. A CA maintains accessible directories of valid certificates, and a list of certificates it has revoked.
Traditionally, PKI functionalities have been used by data terminals with the certificate and keys stored in an external Smart Card. However, as cellular phones merge to data terminals, there will be a need for PKI functions also in the phones. The certificate and keys will then normally be stored in the subscriber card, e.g. in the SIM (Subscriber Identity Module) card as for GSM phones.
For the PKI system to be trusted, there has to exist a secure routine when registering new users by issuing digital certificates. One has to be 100% sure that the one requesting digital certificates is who he or she claims to be. This is normally done in that the user in person shows up at an office, e.g. at a post office, fills in a form and identifies himself by a trusted identification like a passport. When the counter clerk at the post office has verified the identification information, the data form is transmitted electronically to a CA. The CA controls and whitewashes the data and issues a PKI card, either in the form of a SIM card or a Smart Card, together with an activation code. The PKI card and the activation code are now sent by registered mail to the user. Again, the user personally has to appear in the post office and identify himself by, e.g., his passport, for being allowed to receive the mail.
This two-time appearance at an office has turned out to be a problem for the spreading of PKI, simply because people seem to have a resistance against making use of new technology with high entrance thresholds meaning that great initial efforts have to be made. Also, the process is naturally time consuming, and at least one week will lapse from the certificate is ordered to the user has got access to PKI functions.
From the issuer of digital certificates point of view, the costs of the issuing process are relatively high, especially because of the execution and sending of the registered mail.
Thus, there is a need for simplifying the issuing process for the benefit for both the issuer and the user.